Site Map
Contacts
Follow us on Facebook Follow us on Twitter YouTube channel
Centro de Astrofísica da Universidade do Porto

Simultaneous optical and X-ray observations of flares and rotational modulation on the RS CVn binary HR 1099 (V711 Tau) from the MUSICOS 1998 campaign

D. Garcia-Alvarez, B. H. Foing, D. Montes, J. Marques Oliveira, S. Messina, J. G. Doyle, M. Rodonó, A. F. Lanza, J. Abbott, T. R. Bedding, T. D. C. Ash, I. K. Baldry, D. A. H. Buckley, J. Cami, H. Cao, C. Catala, K. P. Cheng, A.-M. Hubert, A. Domiciano de Sousa Jr., J.-F. Donati, E. Janot-Pacheco, J. X. Hao, L. Kaper, A. Kaufer, N. V. Leister, J. E. Neff, C. Neiner, S. Orlando, S. J. O'Toole, D. Schäfer, S. J. Smartt, O. Stahl, J. Telting, S. Tubbesing

Abstract
We present simultaneous and continuous observations of the Hα, Hβ, He I D3, Na I D1, D2 doublet and the Ca II H & K lines for the RS CVn system HR 1099. The spectroscopic observations were obtained during the MUSICOS 1998 campaign involving several observatories and instruments, both echelle and long-slit spectrographs. During this campaign, HR 1099 was observed almost continuously for more than 8 orbits of 2.8 deg. Two large optical flares were observed, both showing an increase in the emission of Hα, Ca II H & K, Hβ and He I D3 and a strong filling-in of the Na I D1, D2 doublet. Contemporary photometric observations were carried out with the robotic telescopes APT-80 of Catania and Phoenix-25 of Fairborn Observatories. Maps of the distribution of the spotted regions on the photosphere of the binary components were derived using the Maximum Entropy and Tikhonov photometric regularization criteria. Rotational modulation was observed in Hα and He I D3 in anti-correlation with the photometric light curves. Both flares occurred at the same binary phase (0.85), suggesting that these events took place in the same active region. Simultaneous X-ray observations, performed by ASM on board RXTE, show several flare-like events, some of which correlate well with the observed optical flares. Rotational modulation in the X-ray light curve has been detected with minimum flux when the less active G5 V star was in front. A possible periodicity in the X-ray flare-like events was also found. Based on observations obtained during the MUSICOS 98 MUlti-SIte COntinuous Spectroscopic campaign from Observatoire de Haute-Provence, France, Kitt Peak National Observatory, USA, ESO La Silla, Chile, Mt. Stromlo Observatory, Australia, Xinglong National Observatory, China, Isaac Newton Telescope, Spain, Laboratório Nacional de Astrofísica, Brazil, and South African Astronomical Observatory, South Africa. Contemporaneous observations from Catania, Italy and Fairborn Observatories, USA, and on data obtained with the Rossi X-ray Timing Explorer.

Astronomy and Astrophysics
Volume 397, Page 285
January 2003

>> ADS>> DOI

Institute of Astrophysics and Space Sciences

Institute of Astrophysics and Space Sciences (IA) is a new but long anticipated research infrastructure with a national dimension. It embodies a bold but feasible vision for the development of Astronomy, Astrophysics and Space Sciences in Portugal, taking full advantage and fully realizing the potential created by the national membership of the European Space Agency (ESA) and the European Southern Observatory (ESO). IA resulted from the merging the two most prominent research units in the field in Portugal: the Centre for Astrophysics of the University of Porto (CAUP) and the Center for Astronomy and Astrophysics of the University of Lisbon (CAAUL). It currently hosts more than two-thirds of all active researchers working in Space Sciences in Portugal, and is responsible for an even greater fraction of the national productivity in international ISI journals in the area of Space Sciences. This is the scientific area with the highest relative impact factor (1.65 times above the international average) and the field with the highest average number of citations per article for Portugal.

Proceed on CAUP's website|Go to IA website